This invention relates to valves for fluid conduit systems and more particularly to an improved combination shut-off check and pressure surge relief valve.
In many forms of fluid conduit systems such as municipal water systems a shut-off valve is required and also one that will prevent any reverse flow as well as accommodate extra high level pressure surges in either direction. One valve in the prior art which attempted to accomplish the aforesaid multiple function is described in U.S. Pat. No. 3,721,264. However, in the device described therein a pressure surge relief valve is formed by components situated around the controllable valve stem. This arrangement proved to be a relatively bulky and complicated structure as well as expensive to manufacture. Also, the aforesaid valve structure was unreliable due to the fact that elastomeric O-rings were relied on to provide for sealing of the movable valve member. Such O-rings often caused unsatisfactory operating results because their friction characteristics varied under wet and dry conditions and also with irregular wall surface conditions of the cylinder surrounding the valve structure.
A combination valve of the type disclosed may be connected in a typical household water system to cold as well as hot water sources from which pressure surges may originate. It is necessary that the pressure relief be reliable as well as sensitive and responsive to such momentary surges. Moreover, if possible, any fluid that is allowed to escape during a pressure surge should be prevented from endangering or inconveniencing persons located near the valve. A general object of the present invention is to provide an improved combination valve that overcomes the disadvantages and solves the aforementioned problems associated with similar prior art valves.
A more specific object of my invention is to provide a combination valve of the type described wherein the elements forming a surge relief valve are completely contained within the manually operable valve stem.
Another object of the present invention is to provide a valve that is particularly well adapted for ease and economy of manufacture.
Yet another object of the present invention is to provide a surge relief valve for a combination shut-off and anti-reverse flow valve wherein any fluid expelled during a momentary pressure surge in the valve is prevented from contacting anyone near the valve.
Other objects, advantages and features of the invention will become apparent from a detailed description of one embodiment presented in conjunction with the accompanying drawing.